Increased expression of myelin binding protein in apotransferrin treated cells involves Fyn tyrosine kinase activity

PÉREZ, M.J., ORTIZ, E.H., ROFFE, M., PASQUINI, J.M.

Cancún, México

Congreso; 21st Biennial Meeting of International Society for Neurochemistry and the 38th Annual Meeting of the American Society for Neurochemistry; 2007

We have recently observed that addition to the culture medium of apotransferrin (aTf) acelerates the differentiation of two oligodendroglial (OL) cell lines (N19 y N20.1) (Paez et al., 2004). This effect involves an increase in the expression of the myelin basic protein (MBP) gene. Morphological and immuno-cytochemical analyses indicate that these cell lines represent OL at different stages of development. Fyn tyrosine kinase (Fyn) is a member of the Src family of proteins that  has been shown to play an important role in myelination (Umemori et al., 1994). We have recently shown that aTf activates Fyn in OL primary cultures and in the N19 cell line (Ortiz et al., personal communication).  Studies were done in order to determine if Fyn is involved in the upregulation of the MBP gene promoted by aTf and to investigate the molecular mechanisms participating in this effect. For this purpose a chemical and selective inhibitor for Fyn (PP2) was used. We have investigated the differential distribution of active versus inactive-Fyn in OL and we have found that aTF at short times (i.e. until 6 hours) produces a transient increase in Fyn activation and binding to the Fyn responsive sequence on the MBP promoter. ApoTf also promotes the increase of MBP mRNA in N19 cells. This effect is prevented by the addition of PP2. These results suggest that Fyn could be involved in the action of aTf on MBP expression.